Integral base closure



6, 1958 c. CJLATHAM, JR 2,848,947

- INTEGRAL BASE CLOSURE Filed Feb. 20, 1957 2 Sheets-Sheet 1 INVEN TOR.

CHARLES C- LATHAM JR.

BY I

Aug. 26, 1958 c. c. LATHAM, JR

INTEGRAL BASE CLOSURE v 2 Sheets-Sheet 2 Filed Feb. 20, 1957 INVENTOR.

CHAR LES C. LATHAM JR.

,Unit States to resist pressure in the opposite direction.

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' (Granted under Title 35, U. 5. Code 1952 sec. 266) The invention described herein may be manufactured and used by or for the Government of the United States pef America for governmental purposes without the payln'i'elntpf any royalties thereon or therefor.

' 'This invention relates generally to base detonating fuzes Q for 'explos'iveshells, and more particularly to a base closure for such fuzes.

In the presently employed base detonating fu'ze, there is always present the possibility of undesirable gas leakagea'round the fuze. The present fuze is made of several component parts including effecting a gas seal around the fun by means of calking with lead and copper. The

latter metals are of a strategic nature, especially during period o f national emergency and armed conflict. In order to efiectively apply the gas seal, a number of maoper'ation are required on the base closure to accommodate "the copper and lead seals.

Therefore, it is the principal object of this invention to provide a base closure for a base detonating fuze which will insure a positive gas seal to prevent leakage around the fuze, conserve strategic copper and lead materials,

' eliminate a number of machining and assembling steps,

and. which can be more cheaply and economically produced than the presently employed base closure.

Another object of this invention is to provide a base closure which is compact so that it can be packed and shipped empty, thereby reducing transportation cos-ts by elimination of an explosive hazard and its premium cost. The compactness of the base closure of this invention will greatly assist in saving storage space.

It has been found with the current base closure that in attempting to unscrew, replace, and recalk the base in order to refuze, there has been approximately 25% disassembly failures. Even in those fuze plugs which remained assembled with the shell loading assembly when the fuze is removed, evidence of thread stripping in varying degrees has been found. The reuse of a base plate or closure with stripped threads may, when the round of explosive shell is fired, result in the force of the set-back being placed entirely upon the calking which is designed Hence, a further object of this invention is to provide a base closure which can be readily disassembled to replace a fuze, especially in the field, and easily assembled without the attendant difliculties and dangers encountered with the currently used base closure design, and would increase the facility with which consistent recovery of the shell loading assembly can be accomplished without breaking or weakening the gas seal or requiring replacement of the gas seal.

The above and other objects may 'be attained by employing this invention which embodies among its features I a base closure including .a single casting, integrally formed closure body having axially aligned cavities or recesses opening through opposite ends of the body, one of the recesses defining a cup for receiving a tracer device therein, the other recess adapted to have releasably secured therein one end of a fuze body, and a percussion plunger assem- .2 bly, and a partition wall which defines a barrier between the two cavities or recesses preventing communication therebetween.

Other features include a restraining spring in the recess receiving the percussion plunger assembly and one end of the -fuze body, the spring surrounding the upper portion of the plunger assembly and extending into "a recessed seat provided in the one end of the fuze body.

Other objects, features and advantages will become apparent from the following detailed description, forming the specification, taken in conjunction with the accompanying drawings, in which:

Figure 1 is a perspective viewshowing a complete round of explosive 'shel-l employing the base closure of this invention;

Figure 2 is an exploded perspective view of the base closure, with the closure body in quarter section, of the base closure and associated tracer device and fuze body;

Figure 3 is a sectional view, on a somewhat enlarged scale, taken substantially along line 3-3 of Figure .1; and

Figure 4 is a cross sectional view taken along line 4-4 of Figure 3.

With continued reference to the drawings, the round of explosive shell is generally indicated at 10 and has a nose end 12, an internally threaded open base end 14, and a rotating band 16. The base end 14 is closed by a base closure, generally indicated at '18, embodying this invention.

The base closure :18 is made as a one-piece, integral unit and comprises a generally cylindrical closure body 20 provided with a peripheral flange 22 "adjacent one end thereof and extending perpendicularly therefrom. That portion of the body 20 extending .from the flange 22 to i the end of the body remote from the flange is provided with left-hand external threading 24 to be screwed into complementary internal screw threading at the base end '14 of the shell 10. A pair .ofdiametrically opposed tool receiving bores 26 are drilled into the face 30 of'the flange '22 remote from the threaded portion 24 of the body 20. Thus, 'a common tool, such as a spanner wrench, can be employed to tighten the closure onto the shell and to remove the closure from the shell with rapidity and ease. This facilitates removal of the closure, especially in the field, for purposes of refuzing the shell, as will appear hereinafter.

A boss 28 in the form of a frustrated cone extends outwardly from the face 30 concentrically about the axis of the body 20. A recess or cavity 32 is bored into the top of the boss 28- along the axis of the closure body and is provided with internal left hand threading 34. The recess 32 defines a cup into which is removably threaded an externally threaded tracer device 36 having its outer end provided with diametrically opposed flat surfaces 38 to cooperate with a suitable tool for tightening the device into the cup.

Into the face 40, remote from face 30, a cavity or recess 42 is drilled. The recess 42 is counterbored as at 44, and the counterbase is chased to provide internal lefthand threads 46. The counterbore 44 defines a shoulder 48 in the recess 42. That portion of the recess or cavity 42 extending from the shoulder 48 to the bottom 50 of the recess defines a seat for a usual type precussion plunger assembly generally indicated at 52.

With the larger dia-metered portion 54 placed into the seat of recess 42, the smaller diametered portion 56 projects above the shoulder 48 so that the percussion pin 58 contained in the assembly 52 will be in proper position to strike the fuze body and usually carries the detonating charge, generally indicated at 60, when the complete round is assembled.

The fuze body 60 is of elongated cylindrical form having left-hand threads 62 provided adjacent one end 64 thereof to be threadingly received in the counterbore 44. As clearly seen in Figure 3, a bore 66 is drilled centrally into the face of the fuze body through the end 64 so as to partially receive therein the portion 56 of the assembly 52.

A shoulder 68 is formed on the assembly 52 between the larger and smaller diametered portions 54 and 56 to provide a seat for one end of a retaining spring 70 disposed in surrounding relation about the portion 56. The other end of the spring 70 is seated against the bottom of the bore 66 in the fuze body. Spring 70 will maintain the assembly in spaced relation to the fuze body until such time as impact of the nose end 12 of the shell will cause the assembly to move forward against the effort of spring 70 causing the percussion pin 58 to strike the bottom of bore 66 of the fuze body and initiate detonation.

In the assembly of the closure 18, a suitable adhesive thread cement will be used on the threads 46 to assure that the fuze body or fuze loading assembly 60 will not separate prematurely from the base closure 18 in the event of subsequent disassembly.

From the foregoing, it will be seen that the base closure 18 has a recess or cavity 32 and 42 coaxially aligned along the axis of the body 20 and opening through boss 28 and face 40 respectively at opposite ends of the closure body. This leaves a partition wall or barrier 72 of considerable thickness between the recesses 32 and 42 to prevent communication therebetween. Thus, escape of gases is limited to those which can flow through the threaded connection of the closure body and the base end 14 of the shell 10. In order to insure against gas leakage in this area, a gasket 74 of suitable material is disposed between the shell base end face and the face 40 of the closure body. i

It will be noted that the base closure 18 may be made of lightweight metal, such as aluminum, to increase the speed of machining and reduce the overall weight of the shell without decreasing its effectiveness.

While there are shown and described the preferred embodiments of the invention, it is tobe understood that the structure is susceptible to change and modification within the practicability of the invention and therefore should 2e limited only by the scope of the claim appended ereto.

What is claimed is:

In combination, an explosive shell having an axial line of symmetry, including a forward nose end, a rotating band, and an open internally threaded rearward end, an integral generally cylindrical base closure for said open rearward end comprising a body defining a peripheral flange adjacent its rearward end and extending perpendicularly therefrom, a forwardly extending threaded portion for threadable engagement with said internally threaded ally disposed bore opening through its forward end and an internally threaded counter bore forwardly of said axially disposed bore, there being a partition wall between said bores in said forwardly extending threaded portion and said bore in said boss, a fuze mechanism for said shell comprising a percussion. cup slidable in said axial bore in said body, a reduced cylindrical member fixed in said percussion cup and extending beyond, a firing pin carried by said cylindrical member, a detonator carrier defining a tubular body, closed at its forward end and having external threads adjacent its open end for engagement with said internally threaded counterbore in said tubular body in said base closure, said tubular body having a counterbore adjacent its open end thereof, a coil spring encircling said reduced cylindrical member extending beyond said percussion cup at one of its ends and having its other end received in said counterbore in said tubular body, normally biasing said cup, said reduced cylindrical member and said firing pin from said detonating charge in said tubular body and means sealing between said base closure and said shell comprising an annular gasket disposed between said peripheral fiange on said base closure and the rearward face of said shell.

References Cited in the file of this patent UNITED STATES PATENTS 2,463,154 Coppotelli Mar. 1, 1949 2,504,163 Summerbell Apr. 18, 1950 FOREIGN PATENTS 541,027 Germany Jan. 8, 1932 

